F2 F3 visual external engine differences

What's the easiest way to tell the difference between an F2 and F3 engine if they are sitting side by side? Are there any differences in the case at all that are obvious?

 

If you look below the head and carbs on the block, a F3 will have a thick wire for the speed sensor. The F2 does not have it. Ic ould be snipped of so look closely.

 

Also, engine #'s on the F3 start with a 240.
F2 & is 230 & prior.

 

F3 cylinder head is a brighter aluminum silver than the F2.The F2 cylinder head's shade of silver is identical to the cases.Don't even have to drop it out of the bike to tell.

F3 #s on the cases start with PC25E-24++++++

 

Thanks